Combine harvesters are equipped with an attachment which has a reel for collecting the harvested crop, and a cross auger, situated downstream from the reel, which compacts the harvested crop and conveys it toward the center to an inclined conveyor. The inclined conveyor is situated in a duct, and conveys the harvested crop into a threshing device of the combine harvester.
Inclined conveyors of this general type for combine harvesters are well known in the prior art, for example from DE 1199039, U.S. Pat. No. 3,555,790, DE 4132246 A1, DE 4311054 C2, DE 102009036104 B4, EP 1733607 B1, and DE 102005027841 A1. These inclined conveyors have at least two endless traction means which extend in parallel to one another and which are interconnected by carrier bars situated transversely with respect to the conveying direction. The carrier bars feed the harvested crop into an undershot conveyor duct of a threshing unit of the combine harvester. The carrier bars are connected to the traction means by screws.
The endless traction means revolve in a conveyor duct whose end faces are open toward the reel and the threshing unit, but which are otherwise closed all around. The conveyor duct is divided into an undershot conveyor duct and an overshot return duct by means of an intermediate floor which is situated between the upper run and the lower run of the traction means and which extends over a large portion of the length of the conveyor duct.
Standard steel profiles such as U, L, and T profiles which are not heat-treated are used as carrier bars according to the prior art. These carrier bars have a low profile height and a limited conveying action due to their low form resistance to the harvested crop. In addition, the profiles are very smooth, and therefore have a very low degree of frictional engagement with the harvested crop. Due to the friction of the harvested crop at the bottom of the conveyor duct and the moderate entrainment effect of the carrier bars, during operation there is a considerable difference in speed between the carrier bars and the harvested crop stream (slip). This results in a high level of energy consumption, a high degree of wear, a high load on the traction means, and a premature threshing effect.
It is known from the prior art to eliminate or at least reduce the above-described slip between the carrier bars and the harvested crop stream via aerodynamic measures. A combine harvester is described in U.S. Pat. No. 3,555,790 in which a threshing cylinder situated at the outlet of the conveyor duct of the inclined conveyor is redesigned in such a way that it acts as a fan, and thus exerts a suction effect on the harvested crop present in the conveyor duct.
A similar approach is described in EP 1 733 607 B1. The chains of this inclined conveyor, which are used as traction means, revolve around a lower traction means guide and an upper traction means guide. The upper traction means guide has a drive shaft upon which chain wheels used for driving the chains rest in a rotationally fixed manner. A drum which is provided with bars or pins on its shell is situated on the drive shaft, between the chain wheels. Due to this design, the upper traction means guide likewise exerts a suction effect on the harvested crop present in the conveyor duct, thus reducing the difference in speed between the carrier bars and the harvested crop stream.